This proposal is to request support for a Keystone Symposia meeting entitled "MicroRNA and Cancer", organized by Frank J. Slack and Amy E. Pasquinelli, which will be held in Keystone, Colorado from June 10 - 15, 2009. MicroRNAs have recently emerged as key regulators of gene expression during development and are frequently mis-expressed in human disease states, in particular cancer. MicroRNAs act to promote or repress cell proliferation, migration and apoptosis during development, all processes that can go awry in cancer. Thus, microRNAs have the ability to behave like oncogenes or tumor suppressors. Their small size and molecular properties make miRNAs amenable as targets and therapeutics in cancer treatment. While hundreds of human microRNAs are known, relatively little is known about their roles and targets. This meeting will focus on the exciting biology of microRNAs in controlling developmental and cancer processes like cell proliferation, differentiation, cell cycle, apoptosis and metastasis. It will also focus on the latest efforts to harness the power of these small RNAs as agents in the fight against cancer. Public Health Relevance: Oncologists have made progress in early diagnosis and treatment of cancer, a huge worldwide public health issue, however there still remains much room for improvement in this area. miRNAs have generated much excitement because they are intricately involved in cancer, and provide drugable targets and small molecule therapeutics that could see widespread use in treating cancer. This meeting will assemble investigators from many different fields - RNA, bioinformatics, genomics and cancer biology - to develop new ideas regarding the means by which miRNAs impact tumor initiation and progression.